sendmail help

[Nick D'Angelo]

I host a web site running Redhat 7.1 on an HP Kayak PC and act as their mail server. But I have one problem, sending mail.

I have configured my mail services so that the client, I'll call them farside, can remotely pick up their mail no problem.

The problem is if they want to send mail. Their email connection is refused at my end.

Can I set the farside up to send mail through my Redhat box as I am the mail server?

What happens if I get some additional remote clients that need mail also and they will probably be dynamic addresses?

Do I need to setup some sort of trust with that remote client?

I appreciate your help,

ND